Cutting tool

ABSTRACT

The tool presents a combination of specially lune-shaped, object-excising cutter rigidly mounted on a transparent base, and a similarly shaped stripper also carried by the base and resiliently biased to yield and move within and relative to the cutter. The cutter has a cutting edge defining a crescent-like cutter contour, this edge projecting from the mounting base in the direction in which the tool is manually translated in a cutting operation. The cutter is a two-piece one presenting generally nested, oppositely facing surfaces of arcuate lunar shape; and these surfaces are respectively mated externally, mounted and braced by transparent Lucite blocks, which coact to constitute the cutter holding body. To this end each cutter knife edge or razor blade component is rigidly secured to its own mated mounting block by screws tapped into the latter; and said blocks are in turn rigidly secured together by a pair of bolts or studs spanning the meeting line of the blocks. The knife edges or blades of the two cutter lunes converge at opposite extremities to a quite close adjacency to one another, but are nevertheless still a trifle spaced sufficiently to avoid forming thin feather edges on the excised piece, in the interest of insuring a clean stripping of the latter from the cutter. The stripper plate is normally disposed in the horizontal plane of the actual razor edge of the cutter. Springs enable the stripper plate to yield upwardly within the cutter as it slices downwardly through the excised sheet, then as fully compressed to automatically eject the excised product from the cutter.

United States Patent [191 Williams 1 CUTTING TOOL [76] Inventor: JohnWilliams, 18331 Tipsilo Lake Rd., Fenton, Mich. 48430 [22] Filed: Aug.10, 1973 [21] Appl. No.: 387,483

[52] US. Cl. 30/130, 76/107 R [51] Int. Cl B26b 3/08 [58] Field ofSearch 30/128, 130, 301, 302, 30/303, 316, 344, 358; 83/684, 128; 76/107R [56 References Cited UNITED STATES PATENTS 625,636 5/1899 Bass 30/1301,082,985 12/1913 Wilder 83/684 X 1,649,803 1l/l927 Boirsky 30/1302,612,123 9/1952 Nord 30/316 2,799,929 7/1957 Kurianski.. 30/3012,821,871 2/1958 Sarno 83/128 X 3,531,863 10/1970 Sandborn 30/301Belknap [57] ABSTRACT The tool presents a combination of speciallyluneshaped, object-excising cutter rigidly mounted on a [451 Feb.11,1975

transparent base, and a similarly shaped stripper also carried by thebase and resiliently biased to yield and move within and relative to thecutter. The cutter has a cutting edge defining a crescent-like cuttercontour. this edge projecting from the mounting base in the direction inwhich the tool is manually translated in a cutting operation. The cutteris a two-piece one presenting generally nested, oppositely facingsurfaces of arcuate lunar shape; and these surfaces are respectivelymated externally, mounted and braced by transparent Lucite blocks, whichcoact to constitute the cutter holding body. To this end each cutterknife edge or razor blade component is rigidly secured to its own matedmounting block by screws tapped into the latter; and said blocks are inturn rigidly secured together by a pair of bolts or studs spanning themeeting line of the blocks. The knife edges or blades of the two cutterlunes converge at opposite extremities to a quite close adjacency to oneanother, but are nevertheless still a trifle spaced sufficiently toavoid forming thin feather edges on the excised piece, in the interestof insuring a clean stripping of the latter from the cutter.

The stripper plate is normally disposed in the horizontal plane of theactual razor edge of the cutter, Springs enable the stripper plate toyield upwardly within the cutter as it slices downwardly through theexcised sheet, then as fully compressed to automatically eject theexcised product from the cutter.

19 Claims, 7 Drawing Figures PATENTEDFEBI l 1975 SHEET 10F 3 F'IG.Z

PATENHED 3.864.829

SHEET 2 OF 3 minno H915 3.864.829

SHEEI 30F 3 lllll PIC-1.7

Lllll CUTTING TOOL BACKGROUND OF THE INVENTION 1. Field of the InventionThe tool has wide potential use in the cutting of product pieces fromrelatively thick, normally cut-resistant sheet material, for examplefiberglass-impregnated sheeting, or alternatively in the excision ofsuch material to internally shape and remove slug material therefrom. Aspecific instance is in the formation of aerodynamic guide vanes offiberglass for installation in duct work or a related field; and thepresent disclosure is therefore addressed to that particularillustrative use, although many others will, of course, suggestthemselves.

2. Description of the Prior Art A search has revealed the followingpatents, none of which bear with any particular pertinence on featuresof the improvement presently to be described:

Haas Brady Mitchell Pieper The improved tool of the invention permits aconsiderable mass type of production of various hard-to-cut,non-metallic sheet objects, such as the fiberglass duct vanes instancedabove by a simple repetitive manipulation of the tool, involving onlysuccessive placements of the tool at appropriately spaced areas of asheet to be excised, each followed by a depression of the tool with butmoderate force to cause the tools special razor knife edge cutter topenetrate the sheet, then, upon withdrawing of the tool, toautomatically eject the desired piece from the interior of the cutter.The proportioning of the latter in respect to the sheet thickness issuch that a complete excision of the cutting from the sheet is completedon each operating stroke.

As herein disclosed, the cutter is a hollow one, generallycrescent-shaped in horizontal cross section through its interior, as thelatter is defined by generally similar lune-contoured cutter edges orblades; and the invention in a secondary detail deals with a positionalrelationship of extreme end edges of said blades such as to avoidfeather edges on the excised piece which might obstruct its automaticejection from the cutter by the kick-out or stripper unit which ispreferably associated with the cutter proper as an adjunct of the tool.

As thus consituted of special cutter blade components, the tool has aspecial cutter or blade-mounting base, constituted by molded transparentLucite blocks each shaped to mate accurately with an exposed cuttersurface, and to brace and support the cutter components rigidly fortheir action. The transparency of said components is a great convenienceto an operator in manually manipulating the tool repeatedly and at ahigh rate of production of excised pieces.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary top plan viewof the tool and stripper assembly of the invention, including cutter,cutter mounting base structure, kick-out or stripper unit and a portionof the tools manipulating end hand pieces;

FIG. 2 is a bottom perspective view of the cutter subassembly, thestripper unit having been omitted for clarity;

FIG. 3 is a fragmentary view in transverse vertical section on line 33of FIG. 1, indicating certain dimensional and positional relationshipsof cutter and stripper components, as at the completion of aproductexcising operation on an excised sheet;

FIG. 4 is a view in transverse vertical section on broken line 4-4 ofFIG. 1, showing details of attachment of the cutter to mounting baseblock components;

FIG. 5 is a fragmentary view in horizontal section on line 5-5 of FIG.4, showing a detail of the blade and stripper relationship;

FIG. 6 is a view in vertical section on a line corresponding to line 66of FIG. 1, illustrating the tool in the position of its parts at thecommencement of a product-excising translational stroke; and

FIG. 7 is a view sectioned similarly to FIG. 6, but showing the tool atthe completion of an excision operation, prior to lifting of the tooland automatic ejection of the cut piece by the stripping unit of thetool.

DESCRIPTION OF A PREFERRED EMBODIMENT FIGS. 1 and 2 best show the toolof the invention, generally designated 10, to comprise an elongatedrectangular transparent tool-supporting base 11 composed ofa pair ofcoating block-like members 12 and 13, each formed of the transparentmethyl methacrylate material known as Lucite, or in the alternative,members of glass or an equivalent plastic may be employed. They aretypically of, say, /8 inch thickness, 8 inch length and, as assembled toform the composite base 11, they aggregate approximately 3 inches infront-to-rear width, as assembled to the fiberglass piece orpartexcising cutter which they rigidly mount, said cutter beinggenerally designated by the reference numeral 14. Inasmuch as thatcutter determines the contours of a pair of mutually facing uprightsurfaces l5, 16 of the respective base block members 12, 13, adescription in detail of the cutter 14 is here in order.

It in turn is in the form of a pair of hardened steel cutter blades l8,19, which will respectively face the base block surfaces l5, l6; andblades l8, 19 are ofa generally similar lunate arcuate outline, althoughformed on different radii of curvature. Thus, blade 15 may typically beformed on a radius of 2-13/16 inches, while the milder arced blade 16would have a radius of, say 3-1 1/16 inches. They have a common overallheight, in the direction from which they project from block 11 ofapproximately 1- /2 inches, and as their unsharpened edges come flushwith the top of mounting base 11, their sharpened razor edges 20 willproject and terminate "Vs inch beneath the bottom of block 11. Thistypically will be a trifle less than the thickness of a sheet S (FIGS. 6and 7) of the glass fiber matting or padding from which a vane piece orpart P is excised; but allowing for the compressibility of this materialunder the downward thrust of tool 10, the operation is one of totallyslicing through sheet S and wholly excising the piece P therefrom in aclean and precise peripheral outline.

To this end, the cutter blade edges 20 are precision ground andrazor-sharpened, enabling a slicing penetration of the cut-resistantsheet S to be accomplished with a minimum of manual effort on the partof the operator. Typically, in a cutter assembly such as that hereinshown, the horizontal straight line length of cutter 14 from end to endof its crescent or lunate length will be in the order of 5- /1 inches.

Reference should be had in particular to FIG. 5 in conjunction with theother figures in regard to more specific details and the relationship ofthe cutter blades l8, 19. These will each be, say, of a thickness of0.0156 inch; and the blade 19 is continuous end to end in its plainarcuate contour on the 2-13/16 inch radius mentioned above, and ispreferably sharpened at its oppo site upright ends 22. On the otherhand, the second blade 18, although continuously contoured on itsabovedescribed radius over by far the major portion of its length, is atits end extremities angled at 45 toward blade 19 and sharpened at 23along this angle to provide a knife edge coming very close to if notcontacting the terminus of the knife edge 22 of blade 19. Thespecifically designated sharpenings 22, 23 are of course continuationsof the major blade sharpenings at 20. There is thus defined an overallcrescent-shaped cross section of the cutter 14 in a horizontal plane at90 to the upright blades l8, 19 which, as defined at its meetingsharpened ends, produces a clean slicing cut through the sheet S withoutpossibility of tear raggedness and without likelihood of the latterclogging the hollow interior of cutter 14, hence impeding the desiredclean and positive ejection of the incised piece P from the cutter bythe kick-out or stripper unit of the invention, later described indetail.

As shown in FIGS. 1, 2 and 4, the blades 18, 19 are rigidly mounted toblocks 12 at the latters mutually facing surfaces by pairs of flat-headscrews 24 threaded into tapped openings in said blocks, with thescrew-heads coming flush with the opposite inner surfaces of the blades.

In conformity with the arcuate contours of the blades l8, 19 asdescribed above, the mounting Lucite blocks l2, 13 are specially shapedat the respective mutually facing surfaces 15, 16 thereof mentionedabove. Thus, the block 12 presents its concave facing surface 15 inflush mating and clamping engagement with the lune blade component 18,and the other block 13 presents its convex face 16 in similar mating andclamping engagement with the concavity of blade 19.

As extended beyond the thus-defined, crescentshaped outline of blade 14,the mounting blocks 12 and 13 have flush contacting engagement with oneanother along a horizontal upright interface zone 25, which extends thefull remaining longitudinal dimension of said blocks; and a pair ofhorizontal elongated studs 26, as received in counterbored holes throughblock 12 and threaded into the block 13 through the meeting interface25, rigidly clamp the blocks together in their own corresponding rigidclamping engagement with cutter blades 18 and 19. Studs 26 arepreferably of the Allenhead type, coming flush with the front uprightsurface of base mounting block 12.

Cutter base 11 is completed adjacent its opposite longitudinally spacedends by a pair of like hand grips 28. These may be ofa l6-gauge sheetsteel, flat at the inner portions thereof and secured from above toLucite base block 12 by a set of flat head screws 29 taking threadedlyinto the material of said block. Otherwise, the hand grips 28 are rolledat 30 along portions thereof which project upwardly and outwardly fromthe fiat screwed portion thereof for a convenient and comfortable gripby an operataor in manipulating the tool.

FIGS. 3, 6 and 7 best shown, as optionally assembled to the cuttersub-assembly mentioned above, a kick-out or stripper unit orsub-assembly, generally designated 32. It comprises a pair of uprightguide pins, rods or posts 33, which may be in the form of elongatedmachine bolts or studs. These project well upwardly above the top ofcutter mounting base 11, and are rigidly fixed at their lower ends tothe mounting block 12, as at lower stud ends threaded or otherwisemounted fast in upright holes 34 in block 12. As appears in FIG. 1, thestud rods 33 are located outwardly to either side of the crescent zoneoccupied in mounting base 11 by the cutholes in the guide bar 35, andbeing fixedly secured to said bar by nuts 41 threaded on the screws frombeneath and from above said bar.

Stripper plate 40 is conformed to correspond with the cross sectionalhollow interior area of cutter 14, but, of course, of somewhat lesserperimeter to enable a vertical relative shift of plate 40 within thecutter in its initial engagment with the sheet S and its ultimate actionin expelling piece or part P from the cutter. In its inoperative andfully downwardly extended position, the stripper 40 comes horizontallyflush with the sharpened razor edges 20 of the cutter.

In use, with the fiberglass sheet S to be cut appropriately laid out ona suitable rigid base B (FIGS. 6 and 7) the combined tool 10 is held bythe hand grips 30 and placed atop the sheet, as depicted in FIG. 6, withthe kick-out plate 40 and cutter knife edge formations 20 disposedcoplanar and in engagement with the top surface of the sheet. Theoperator now applies a steady downward force on the tool until thecutter blade 14 engages fully downwardly upon base B, as appears in FIG.7, the mounting base 12 and cutter compressing the sheet to some extentas the excision of vane part P is completed.

FIG. 7 shows that the stripper plate 40 rises in the interior of blade14 as this takes place. The operator then lifts tool 10, preferablyexerting a degree of upward sustaining force on the guide bar 35,sufficient to hold stripper plate 40 in its position relative to blade14 shown in FIG. 7, until the tool is cleared from sheet S. He will thenrelease the guide bar 32, whereupon the compressed coil springs 36 willoperate the bar to expell the part P from the cutter.

This procedure may be repeated at a high rate of production speed, thetransparency of the Lucite base 11 greatly assisting the operator inpositioning the tool for successive lunate cuts in close adjacency toone another on sheet S. This, of course, conserves material and reducesits cost.

What is claimed is:

l. A cutting tool comprising a rigid base fixedly supporting a cutterfor an excising operation on a sheetlike object, said cutter presentinga knife edge defined by two knife edge portions of generally similarlunate contour, said knife edge being exposed well to a side of saidbase and shaped in the outline of an area on said object which isexcised from the latter by the tool, said base having a lunate-shapedopening presenting mutually facing surfaces respectively shaped tocomplement and mate with opposite outwardly facing surfaces of saidknife edge portions which partly extend into said lunate-shaped opening,which mutually facing surfaces of said opening have fixed mating andholding engagement with the respective outwardly facing surfaces of saidknife edge portions, 21 stripping unit mounted on said base to act fromthe latters side opposite that on which said knife edge portions areexposed, said unit comprising a stripping member of lunate-shapedoutline slidably movable between and relative to said knife edgeportions in engagement with said object area during excision of thelatter, rod means fixed on said base and extending from said oppositebase side, and a guide piece spaced from and fixed on said strippingmember and guided on said rod means in said movement of said strippingmember.

2. A cutting tool comprising a rigid base fixedly supporting a cutterfor an excising operation on a sheet like object, said cutter presentinga knife edge exposed well to a side of said base and shaped in theoutline of an area on said object which is excised from the latter bythe tool, said base presenting mutually facing surfaces respectivelyshaped to complement and mate with opposite outwardly facing surfaces ofsaid cutter knife edge, which mutually facing surfaces of the base havefixed mating and holding engagement with the respective outwardly facingsurfaces of said knife edge, and a stripping unit mounted on said baseto act from the latters side opposite that on which said knife edge isexposed, said unit comprising a stripping member conformed in a generaloutline of the excised object and slidably movable within and relativeto said cutter in engagement with said object during excision of thelatter, and spring means acting between said base and said strippingmember in resiliently opposing said relative motion of the latterconcurrently with the excising operation of said cutter, said springmeans returnbiasing the stripping member after excision of the object toexpel the latter from within the cutter.

3. The cutting tool of claim 2, in which said base is transparent forviewing of the object and excised area by a user of the tool.

4. The combination of claim 2, in which said base comprises a pair ofbase members presenting said mutually facing surfaces, said base membersare ofa lighttransmitting material.

5. The combination of claim 2, in which said base comprises a pair ofbase members presenting said mutually facing surfaces, said base membersare of a lighttransmitting material and the base is equipped with handlemeans corresponding which it and the cutter are manipulated in theexcising operation.

6. The combination of claim 2, in which said knife edge of the cutterincludes a pair of knife edge portions of generally similar arcuatecontour spaced laterally from one another in a generally nested relationof correspopnding convexities of said portions as supported between saidmutually facing base member surfaces.

7. A cutting tool comprising a rigid base fixedly supporting a cutterfor an excising operation on a sheetlike object, said cutter presentinga knive edge exposed well to a side of said base and shaped in theoutline of an area on said object which is excised from the latter bythe too], said base comprising a pair of members presenting mutuallyfacing surfaces respectively shaped to complement and mate with oppositeoutwardly fac ing surfaces of said cutter knife edge, which mutuallyfacing surfaces of the base members have fixed mating and holdingengagement with the respective outwardly facing surfaces of said knifeedge, said knife edge of the cutter being defined by at least two knifeedge portions each matingly engaged and held at a shaped facing surfaceof a base member, and a stripping unit mounted on said base to act fromthe latter's side opposite that on which said knife edge is exposed,said unit comprising a stripping member conformed in the general outlineof the excised object and slidably movable between and relative to saidcutter members in engagement with said object area during excision ofthe latter, rod means fixed on said base and extending from saidopposite base side, a guide piece fixed on said stripping member andguided on said rod means in said movement of the stripping member, andcoil compression spring means surrounding said rod means and acting onsaid guide piece in resiliently opposing motion of said piece and thestripping member concurrently with the excising operation of saidcutter, said spring means returnbiasing the stripping member afterexcision of the object to expel the latter from within the cutter.

8. The cutting tool of claim 7, in which said base members aretransparent for viewing of the object and excised area by a user of thetool.

9. The combination of claim 7, in which said base members are of alight-transmitting material.

10. The combination of claim 7, in which said base members are of alight-transmitting material and the base is equipped with handle meansby which it and the cutter are manipulated in the excising operation.

11. The cutting tool of claim 7, in which said knife edge portions areof generally similar arcuate contour spaced laterally from one anotherin a generally nested relation of corresponding convexities of saidportions as supported between said mutually facing base member surfaces.

12. The cutting tool of claim 7, in which said knife edge portions areof generally similar arcuate contour spaced laterally from one anotherin a generally nested relation of corresponding convexities of saidportions as supported between said mutually facing of said base members,said knife edge portions terminating in a close relation to one anotherat adjacent ends of said arcuate contours thereof.

13. The cutting tool of claim 12, in which said knife edge portions areof lunate contour, the terminals thereof nevertheless defining anextreme terminal portion of the excised object which has appreciablewidth in the plane of the object.

14. A cutting tool comprising a rigid base having a pair of generallyparallel sides, said base fixedly supporting a cutter for an excisingoperation on a sheetlike object, said cutter presenting a knife edgeexposed well to one of said sides of said base and shaped in the outlineof an area on said object which is excised from the latter by the tool,said base having a cavity presenting a pair of mutually facing surfacesrespectively shaped to complement and mate with opposite outwardlyfacing surfaces of said cutter knife edge which extend into said cavity,said mutually facing surfaces of said base having fixed mating andholding engagement with the respective outwardly facing surfaces of saidknife edge, and a stripping unit mounted on said base to act from theother of said sides of said base opposite said one side on which saidknife edge is exposed, said unit comprising a stripping member conformedin a general outline of the excised object and slidably movable withinand relative to said cutter in engagement with said object duringexcision of the latter, an elongated guide piece on said other side ofsaid base, fastening means connecting said guide piece to said strippingmember to maintain said guide piece and said stripping member in spacedrelation, and a pair of spaced apart guide posts on said other side ofsaid base, said guide posts having end portions carried by said base,said guide posts extending through openings provided in opposite endportions of said guide piece, said guide piece being guided on saidguide posts in said movement of said stripping member during and afterthe excising operation of said cutter.

15. The cutting tool defined in claim 14 wherein said fastening means isadjustable to vary the spacing between said guide piece and saidstripping member.

16. The cutting tool defined in claim 15 wherein said fastening meanscomprises a pair of nut and bolt type fasteners, each bolt having a headengageable with one surface of the stripping member and a threaded stemextending through openings in said base and in said guide piece, withthreaded nuts on the bolt on opposite sides of said guide piece tomaintain said guide piece and said stripping member in said spacedrelation.

17. The cutting tool defined in claim 14 wherein said guide posts are inthe form of elongated bolts threaded to said base.

18. The cutting tool defined in claim 14 wherein means are provided onsaid base for returning said stripping unit after said excisingoperation to a position with said stripping member adjacent said oneside of said base.

19. A cutting tool comprising a rigid base having a pair of generallyparallel sides, said base fixedly supporting a cutter for an excisingoperation on a sheetlike object, said cutter precenting a knife edgedefined by two knife edge portions of generally lunate contour, saidknife edge portions being exposed well to one of said sides of said baseand shaped in the outline of an area on said object which is excisedfrom the latter by the tool, said base having a lunate shaped openingpresenting a pair of mutually facing surfaces respectively shaped tocomplement and mate with opposite outwardly facing surfaces of saidknife edge portions which extend into said opening, said mutually facingsurfaces of said base having fixed mating and holding engagement withthe respective outwardly facing surfaces of said knife edge, said knifeedge portions terminating in a close relation to one another at adjacentends of said lunate contours thereof, the terminals of said knife edgeportions defining an extreme terminal portion of the excised objectwhich has appreciable width in the plane of the object, and a strippingunit mounted on said base to act from the other of said sides of saidbase opposite said one side on which said knife edge is exposed, saidunit comprising a stripping member of lunate shape conformed in ageneral outline of the excised object and slidably movable within andrelative to said cutter in engagement with said object during excisionof the latter, an elongated guide piece on said other side of said base,fastening means connecting said guide piece to said stripping member tomaintain said guide piece and said stripping member in spaced relation,and a pair of spaced apart guide posts on said other side of said base,said guide posts having end portions carried by said base, said guideposts extending through openings provided in opposite end portions ofsaid guide piece, said guide piece being guided on said posts in saidmovement of said stripping member during and after the excisingoperation of said cutter.

1. A cutting tool comprising a rigid base fixedly supporting a cutterfor an excising operation on a sheet-like object, said cutter presentinga knife edge defined by two knife edge portions of generally similarlunate contour, said knife edge being exposed well to a side of saidbase and shaped in the outline of an area on said object which isexcised from the latter by the tool, said base having a lunate-shapedopening presenting mutUally facing surfaces respectively shaped tocomplement and mate with opposite outwardly facing surfaces of saidknife edge portions which partly extend into said lunate-shaped opening,which mutually facing surfaces of said opening have fixed mating andholding engagement with the respective outwardly facing surfaces of saidknife edge portions, a stripping unit mounted on said base to act fromthe latter''s side opposite that on which said knife edge portions areexposed, said unit comprising a stripping member of lunate-shapedoutline slidably movable between and relative to said knife edgeportions in engagement with said object area during excision of thelatter, rod means fixed on said base and extending from said oppositebase side, and a guide piece spaced from and fixed on said strippingmember and guided on said rod means in said movement of said strippingmember.
 2. A cutting tool comprising a rigid base fixedly supporting acutter for an excising operation on a sheet-like object, said cutterpresenting a knife edge exposed well to a side of said base and shapedin the outline of an area on said object which is excised from thelatter by the tool, said base presenting mutually facing surfacesrespectively shaped to complement and mate with opposite outwardlyfacing surfaces of said cutter knife edge, which mutually facingsurfaces of the base have fixed mating and holding engagement with therespective outwardly facing surfaces of said knife edge, and a strippingunit mounted on said base to act from the latter''s side opposite thaton which said knife edge is exposed, said unit comprising a strippingmember conformed in a general outline of the excised object and slidablymovable within and relative to said cutter in engagement with saidobject during excision of the latter, and spring means acting betweensaid base and said stripping member in resiliently opposing saidrelative motion of the latter concurrently with the excising operationof said cutter, said spring means return-biasing the stripping memberafter excision of the object to expel the latter from within the cutter.3. The cutting tool of claim 2, in which said base is transparent forviewing of the object and excised area by a user of the tool.
 4. Thecombination of claim 2, in which said base comprises a pair of basemembers presenting said mutually facing surfaces, said base members areof a light-transmitting material.
 5. The combination of claim 2, inwhich said base comprises a pair of base members presenting saidmutually facing surfaces, said base members are of a light-transmittingmaterial and the base is equipped with handle means corresponding whichit and the cutter are manipulated in the excising operation.
 6. Thecombination of claim 2, in which said knife edge of the cutter includesa pair of knife edge portions of generally similar arcuate contourspaced laterally from one another in a generally nested relation ofcorrespopnding convexities of said portions as supported between saidmutually facing base member surfaces.
 7. A cutting tool comprising arigid base fixedly supporting a cutter for an excising operation on asheet-like object, said cutter presenting a knive edge exposed well to aside of said base and shaped in the outline of an area on said objectwhich is excised from the latter by the tool, said base comprising apair of members presenting mutually facing surfaces respectively shapedto complement and mate with opposite outwardly facing surfaces of saidcutter knife edge, which mutually facing surfaces of the base membershave fixed mating and holding engagement with the respective outwardlyfacing surfaces of said knife edge, said knife edge of the cutter beingdefined by at least two knife edge portions each matingly engaged andheld at a shaped facing surface of a base member, and a stripping unitmounted on said base to act from the latter''s side opposite that onwhich said knife edge is exposed, said unit comprising a strippingmember conformEd in the general outline of the excised object andslidably movable between and relative to said cutter members inengagement with said object area during excision of the latter, rodmeans fixed on said base and extending from said opposite base side, aguide piece fixed on said stripping member and guided on said rod meansin said movement of the stripping member, and coil compression springmeans surrounding said rod means and acting on said guide piece inresiliently opposing motion of said piece and the stripping memberconcurrently with the excising operation of said cutter, said springmeans return-biasing the stripping member after excision of the objectto expel the latter from within the cutter.
 8. The cutting tool of claim7, in which said base members are transparent for viewing of the objectand excised area by a user of the tool.
 9. The combination of claim 7,in which said base members are of a light-transmitting material.
 10. Thecombination of claim 7, in which said base members are of alight-transmitting material and the base is equipped with handle meansby which it and the cutter are manipulated in the excising operation.11. The cutting tool of claim 7, in which said knife edge portions areof generally similar arcuate contour spaced laterally from one anotherin a generally nested relation of corresponding convexities of saidportions as supported between said mutually facing base member surfaces.12. The cutting tool of claim 7, in which said knife edge portions areof generally similar arcuate contour spaced laterally from one anotherin a generally nested relation of corresponding convexities of saidportions as supported between said mutually facing of said base members,said knife edge portions terminating in a close relation to one anotherat adjacent ends of said arcuate contours thereof.
 13. The cutting toolof claim 12, in which said knife edge portions are of lunate contour,the terminals thereof nevertheless defining an extreme terminal portionof the excised object which has appreciable width in the plane of theobject.
 14. A cutting tool comprising a rigid base having a pair ofgenerally parallel sides, said base fixedly supporting a cutter for anexcising operation on a sheet-like object, said cutter presenting aknife edge exposed well to one of said sides of said base and shaped inthe outline of an area on said object which is excised from the latterby the tool, said base having a cavity presenting a pair of mutuallyfacing surfaces respectively shaped to complement and mate with oppositeoutwardly facing surfaces of said cutter knife edge which extend intosaid cavity, said mutually facing surfaces of said base having fixedmating and holding engagement with the respective outwardly facingsurfaces of said knife edge, and a stripping unit mounted on said baseto act from the other of said sides of said base opposite said one sideon which said knife edge is exposed, said unit comprising a strippingmember conformed in a general outline of the excised object and slidablymovable within and relative to said cutter in engagement with saidobject during excision of the latter, an elongated guide piece on saidother side of said base, fastening means connecting said guide piece tosaid stripping member to maintain said guide piece and said strippingmember in spaced relation, and a pair of spaced apart guide posts onsaid other side of said base, said guide posts having end portionscarried by said base, said guide posts extending through openingsprovided in opposite end portions of said guide piece, said guide piecebeing guided on said guide posts in said movement of said strippingmember during and after the excising operation of said cutter.
 15. Thecutting tool defined in claim 14 wherein said fastening means isadjustable to vary the spacing between said guide piece and saidstripping member.
 16. The cutting tool defined in claim 15 wherein saidfastening means comprises a pair of nut and bolt type fasteners, eachbolt having a head engageable with one surface of the stripping memberand a threaded stem extending through openings in said base and in saidguide piece, with threaded nuts on the bolt on opposite sides of saidguide piece to maintain said guide piece and said stripping member insaid spaced relation.
 17. The cutting tool defined in claim 14 whereinsaid guide posts are in the form of elongated bolts threaded to saidbase.
 18. The cutting tool defined in claim 14 wherein means areprovided on said base for returning said stripping unit after saidexcising operation to a position with said stripping member adjacentsaid one side of said base.
 19. A cutting tool comprising a rigid basehaving a pair of generally parallel sides, said base fixedly supportinga cutter for an excising operation on a sheet-like object, said cutterprecenting a knife edge defined by two knife edge portions of generallylunate contour, said knife edge portions being exposed well to one ofsaid sides of said base and shaped in the outline of an area on saidobject which is excised from the latter by the tool, said base having alunate shaped opening presenting a pair of mutually facing surfacesrespectively shaped to complement and mate with opposite outwardlyfacing surfaces of said knife edge portions which extend into saidopening, said mutually facing surfaces of said base having fixed matingand holding engagement with the respective outwardly facing surfaces ofsaid knife edge, said knife edge portions terminating in a closerelation to one another at adjacent ends of said lunate contoursthereof, the terminals of said knife edge portions defining an extremeterminal portion of the excised object which has appreciable width inthe plane of the object, and a stripping unit mounted on said base toact from the other of said sides of said base opposite said one side onwhich said knife edge is exposed, said unit comprising a strippingmember of lunate shape conformed in a general outline of the excisedobject and slidably movable within and relative to said cutter inengagement with said object during excision of the latter, an elongatedguide piece on said other side of said base, fastening means connectingsaid guide piece to said stripping member to maintain said guide pieceand said stripping member in spaced relation, and a pair of spaced apartguide posts on said other side of said base, said guide posts having endportions carried by said base, said guide posts extending throughopenings provided in opposite end portions of said guide piece, saidguide piece being guided on said posts in said movement of saidstripping member during and after the excising operation of said cutter.